Why would Stonhenge have more credibility than Brainbench?
The latter seems to be a legitimate company, whose focus happens
to be certification. If you mean because more people in the
Perl community have heard of Stonehenge than Brainbench,
you miss the point of certifications: being able to
demonstrate your technical ability to non-technical people,
via a standardized objective, third-party test. Not trying
to knock either company (I happen to think pretty highly
of them both), just pointing out that one having
more "credibility" than the other is a silly statement.

I would think (as a potential employer) that a company which
specializes in online certifications would not be as demonstrative
as a company known for Perl training in ensuring that those
who are certified have practiced their skills rather than
simply regurgitate the knowledge from books and
documentation.

Don't get me wrong, though... the test at Brainbech
was't a walk in the park but I was able to pass the exam
a couple of years ago when I was still new to the language
simply by having the book handy.

NOTE:
I wasn't trying to knock Brainbench. I just
think that even non-technical people have technical people
to use as resources. Most people haven't even heard of
Brainbech (technical and non-technical).

Scenario

You mention your certification on your CV

You get the interview

You explain that your certification came from a prominent Perl training/consulting firm (mention "Learning Perl")

Went to join the gridlock to see it
Held an eclipse party
Watched a live feed
I cn"t see tge kwubosd to amswr thus
I tried to see it, but 8000 miles of rock got in the way
What eclipse?
Wanted to see it, but they wouldn't reschedule it
Read the book instead